No problem, no one knows anything until they learn it the first time.
Thats what we are here for, in case you don't feel the need to try and learn it.
The Vanta/LT is an old card, along the lines of 4-16MB. Which means basically that it is struggling somewhat to run what you are seeing. Where did this computer come from? Some resellers supply cards with their system that have been changed somewhat and you must go directly to their site to check for drivers. Other more standard builders supply industry standard cards and you can go to the nvidia site and download which ever drivers you wish. It makes a difference if they will work properly and run or not when you change them.
IF your card/system will run standard drivers even then the latest ones you could probably use from nvidia would be somewhere in the 70.xx series. Later drivers than that will not work with your card as it is to old to use them and not supported.
Another thing I want you to do is run the aquarium and press the "S" key while it is running. Look in the top left corner and copy down what you see there and post it here. If your system is that old we probably want to limit the frame rate somewhat as well so as not to overheat your cpu/system. Remember that the fish in this screensaver are drawn in real 3D, and it taxes older systems to run it continually.